An encephalic surgical operation and a cardiac surgical operation are implemented by observing the diseased region with medical optical equipment, that is, for example, a surgical microscope, and such very delicate operations impose a high strain upon the nerves and, in most cases, requires a long time to perform, which undesirably causes both the surgeons and the support staff, as well as the patient physical and spiritual fatigue.
A medical optical equipment such as a surgical microscope plays a very significant role in advanced surgical operations, and the accessibility of the medical optical equipment has a direct effect upon reducing the time necessary for a surgical operation. The accessibility of the medical optical equipment, namely, the possibility of positioning the medical optical equipment accurately and quickly at an objective position corresponding to the diseased region to be operated upon, the possibility of moving the medical optical equipment away from the region of the operation to, and fixedly positioning the same at, an optional standby position and the stability of the medical optical equipment at a fixed position, is primarily dependent upon the performance of a stand mechanism supporting the medical optical equipment.
Various stand mechanisms for supporting medical optical equipment including stand mechanisms such as those disclosed in Japanese Patent Provisional Publication (Kokai) No. 56-32110 have been proposed. However, those known stand mechanisms are not sufficiently satisfactory with respect to the required accessibility during modern medical operations.